Polymerization of 3-vinylpyridines and latex produced thereby



United States Patent roLYMERrz'ATIoN or AND LATEX PRODUCED THEREBY JamesE. Pritchard, Bartle'sville,.0kla., a'ssignor to Phillips PetroleumCompany, a corporation of Delaware No Drawing. Application August 10,1953 Serial No; 373,442

18 Claims. (Cl. 260-29.6)

aqueous medium in the presence of an acidic material having anionization constant of at least l.0 l0- In a further aspect thisinvention relates to a process which comprises polymerizing, in aqueoussolution, a salt of a monomeric 3-vinylpyridine with an acidic material,said acidic material having an ionization constant at least 1.0 X andless than 1.49 10- and a water solubility of at least 0.2 20 C.

In U. S. Patent 2,491,472, granted December 20, 1949, to Harmon, aprocess is disclosed which comprises polymerizing in aqueous solution asalt of a monomeric vinylpyridine with an acid having an ionizationconstant of at least 1.49 10- -The patentee sets forth suitable acidssuch as glycolic, halogenated acetic, alphabromopropionic, and formic,but states that the mineralacids, such as hydrochloric, phosphoric, andsulfuric, are preferred. Y

While the statements made by the patentee are true as far as certainvinylpyridine compounds are concerned, I have discovered that3-vinylpyridine and its derivatives thereof, can be polymerized inaqueous solution using acids having ionization constants far below thoseset forth by Harmon. Using the process of my invention, it is possibleto prepare many additional types of polymeric materials and some ofthese are especially valuable as emulsifying agents for polymerizationprocesses, such as disclosed in my copending applications, Serial No.255,741, filed October 26, 1951, now Patent 2,746,943, and Serial No.376,231, filed August 24, 1953. Using this particular vinylpyridine,polymerization occurs at a very rapid rate and high conversion levelsare reached. The polymeric salt solution which is obtained can be usedas such or it can be treated with an alkaline material to precipitatethe free polymeric base which can be washed and dried followingprecipitation.

. Each of the following objects is obtained by at least one oftheaspects of this invention.

An object of this invention is to provide a new method of polymerizingvinylpyridines.

A further'object of this invention is to provide a method of makingpolyvinylpyridines which are substantially free from impurities.

A further object of this invention is'to provide a method forpolymerizing 3-vinylpyridine and derivatives thereof, in an aqueoussolution containing an acidic matter having an ionization constant of atleast 1.0 10- Other objects and advantages will be apparent to oneskilled in the art. f g

In accordance with this invention I have found, surgram per 100 cc. ofWater at .glycerophosphate, monosodium malonate,

2,862,902 Patented Dec. 2, 1958 having a vinylidine group in the3-position are susceptible to polymerization in the presence of acidicmaterials hav= ing comparatively low ionization constants. The polymersproduced by this method are clear and colorless and easily distinguishedfrom the types of product obtained using weakly acidic materials whensubjecting 2-vinyland 4-vinylpyridines to polymerization conditions.When an attempt is made to polymerize the 2-vinyland 4- vinylpyridines,orange or yellow colored solutions are obtained and no furtherpolymerization occurs. While I am not certain what exact form ofmaterial this represents, I believe that a stable resonating product,perhaps a dimer, is formed which does not undergo furtherpolymerization.

As stated above, I carry out the polymerization in the presence ofacidic materials which have an ionization constant from at least 1.0 l0and less than l .49 10 and which have a water solubility of at least 0.2gram per 100 cc. of water at 20 C. These materials form water solublemonomeric salts of the 3-viny1- pyridines and I believe that it is thissalt which undergoes acid, hydraz-oic acid, hydrocyanic acid,hydrosulfuric acid, and hypochlorous acid. Another group comprises saltsof inorganic acids such as ammonium chloride, potassium arsenate,disodium dihydrogen pyrophosphate, sodium dihydrogen phosphate, sodiumdihydrogen phosphite, ammonium selenite, and lithium hydrogen sulfate.

Organic carboxy acids and their derivatives, such as acetic acid, adipicacid, alanine, benzoic acid, 13- bromopropionic acid, n-butyric acid,isobutyric acid, camphoric acid, diethylbar-bituric acid, ethylmalonicacid, fumaric acid, gallic acid, glutaric acid, glycine, n-heptoic acid,n-caproic acid, fi-chloropropionic, crotonic (trans) acid, crotonic(iso) acid, hexahydrobenzoic acid, mhydroxybenzoic acid,p-hydroxybenzoic acid, itaconic acid, lactic acid, maleic acid, malicacid, malonic acid, o-methoxybenzoic acid, methylmalonic acid,phenylacetic acid, B-phenylpropionic acid, phthalic acid, pimelic acid,propionic acid, n-propylmalonic acid, pyromucic acid, pyrotartaric acid,succinic acid, tartaric acid, trimethylacetic acid, valen'c acid, andisovaleric acid, are preferred.

Another group includes salts of certain organic carboXy acids which haveionization constants within the range above set forth, such as monsodiumcamphorate, monopotassium citrate, disodium citrate, monolithiummonoammonium oxalate, monosodium succinate, and monosodium tartrate.

'Another group of compounds which are suitable in 7 providing the acidicacid medium for polymerization according to my invention include thefollowing: barbitur'ic acid, thioacetic acid, thiophenol, cyanuric acid,and phenol. Based on cost factors, availability, and ease of operation,I prefer to use, as the acidic material, acetic acid, propionic acid,succinic acid, adipic acid, or sodium dihydrogen phosphate.

Pyridine compounds which can be polymerized according to the process ofthis invention are the 3-vinyl compounds, that is, 3-vinylpyridineitself, and alkyl derivatives thereof. Also applicable are theB-alpha-methyl:

vinyl (isopropenyl) compounds. These compounds can be represented by thestructural formula Where-R is selected fr omthe group consisting of iCH=CH1 and C=CH2 the R s are selected from the group consisting ofhydrogen, alkyl groups, and other groups which are inert on the ring,such as halogen or alkoxygroups, and R is selected from the groupconsisting of R gand-R The various substituted derivatives which aregenerally preferred are those in which the total number of carbon atomsin R and R is not greater than 12 and most frequently these groups aremethyl and/or ethyl. Representative of the compounds which areapplicable are: 2- methyl-S-vinylpyridine (6 methyl 3-vinylpyridine), 2-ethyl vinylpyridine, 2 isopropyl 5 vinylpyridine, 2'- tert dodecyl 5vinylpyridine, 2,3 dimethyl 5- vinylpyridine, 2'- methyl 3vinylpyridine, 2 dodecyl-3- vinylpyridine, 4 tert butyl 3 vinylpyridine,2,5 dihexyl 3 vinylpyridine, 2,6 diethyl 3 vinylpyridine, 2,4,6 triethyl3 vinylpyridine, 2 isopropyl 5 nonyl- 3 vinylpyridine, 3,5divinylpyridine, 2 chloro 5-vinylpyridine, 2,4.- dibromo 6 ethyl 3vinylpyridine, 2,6- dipropoxy 3 vinylpyridine, 2methoxy-S-vinylpyridine, 2 ethoxy 3 fluoro 4 propyl 5 vinylpyridine, 2'-methoxy 3,5 divinylpyridine, and the corresponding 3:isopropenylpyridines.

Any vinyl or vinylidene compounds which. are copolymerizable with the3-vinyl-substituted compounds are applicable in this invention. Thesematerials include styrene, alpha-methylstyrene, halogen-, alkyl-, andalkoxy-substituted styrenes, acrylonitrile, methacrylonitrile, methylacrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate,methyl vinyl ketone, methyl isopropenyl ketone, methyl vinyl ether,conjugated dienes, and the like. The conjugated dienes are preferablythose which contain from four to six, inclusive, carbon atoms permolecule but those containing more carbon atoms per molecule, e. g.,eight,

can also be used. These compounds include 1,3-butadiene,

isoprene, piperylene, methylpentadiene, 2,3-dimethyl-1,3- butadine,chloroprene, and others. Furthermore, various alkoxy such as methoxy andethoxy, and cyano derivatives of .these conjugated dienes can also beemployed.

When preparing copolymers, the material copolymerized with the3-vinyl-substituted pyridine can be employed in an amount up to 90percent by weight of the total monomeric material.

When operating according to the process of this invention, the3-vinylpyridine, either alone or with a material copolymerizabletherewith, is charged to a reactor together with water, an acidicmaterial having an ionization constant of at least 1.0 l0 andappropriate activator and initiator ingredients, and the mixture poly-vmerized. The resulting material is obtained as a clear solution or astable latex depending upon. thetype and,

precipitates and is separated from the serum, washed, and

dried;

The amount of acidic material employed is generally.

that which is sufiicient to eflfect from 25 to 1000, pref- 4 erably from40 to 500, percent of that theoretically required for completeneutralization of the basic nitrogen groups in the pyridine compoundemployed.

Various types of polymerization recipes can be employed such as thepersulfate, persulfate-bisulfite, and iron pyrophosphate-hydroperoxiderecipes; Polymerization temperatures are generally in the range between40 and 1 70 C: When-temperatures aregbelow .the freezing point of theaqueous medium, a suitable antifreeze agent is included inthe-system,,Polymerization recipes chosen are those which,have;been;.-found; mostsuitablefor the temperature used.

The polymeric salts .ofthis invention can be used as emulsifiers for theproduction of new polymer compositions such as are describedin a.copending application, Serial No. 255,741, filed October 26, 1951, andapplication, Serial No. 376,231, filed August 24, 1953, and for textile;treating, Serial No. 274,660, now Patent, No.

' 2,702,763, andSetj. No. 329,450; filed March 3, 1952, and.;. January2, 1953. respectiyely, Various types of rubbery; and; resi nou s'produets; are obtained. when the polymeric,

salts are converted to the free polymeric bases by treatment; with analkaline materi a1.

The.;examples; which follow demonstrate the applica-.

bilityof this process,to 3;vinylpyridines. andshow that verylittle;polymer ization; occurs with. other, vinyl-substi-,.

uted pyridinest Example I in which.2emethyl-5rvinylpyridine. was ..usedin .place. of

' 2rviriylpyridine; The following ;recipe.was employed:

Parts by weight: on e 100= Water. 300' 2S2QB'. 0.9 NaHSO 0:5 1 Acid 50 7Temperature; "C 50 Results are shown below:

Conver- Monomer Acid slon,

percent,

1.5 hours 2-vinylpyridin Acet 10 2-mcthyI-5-vinylpyridine .do2-vinylpyridine H01 98 z-methyl fi-vinylpyri ilne HO]...-. 92 1 ExamplevII.

The-recipe of Example Iv was usedfor the copoly-- Conversion, percent,

1.5 hours 50/50 acrylonitrile/2-vinylpyridine= copolymer 0 50/50acrylonitrile/2-methyl-5-vinylpyridine copolymer 92 Example 111 Therecipe of Example I was employed for.a series,of

polymerization runs using four different vinylpyridine 5,, pyridinecompound. Polymerization was eifected at 50 C. The results were asfollows:

Acetic Conver- Monomer acid, sion,

parts percent,

. 1.6 hours 2-vinylpy 57 l1 4-vlnylpy'r 57 10 2-vinyl-5-ethylpyridine 502-methyl-5-vinylpyridine 50 100 1 Phase separation occurred with yetlittle if an being formed, Y y y polymer Example IV The recipe ofExample I was employed for a series of polymerization runs using thefour different vinylpyridine compounds employed in Example III. Two molsof acetic acid per mol of the vinylpyridine compound was used in eachcase. Polymerization was elfected at 50 C. Results of polymerizationsafter 1.5 hours and 20 hours are shown below: i

Acetic Conversion, percent Monomer acid, parts 1.5 20 hours2-vlnylpyridine 114 12 12 4-vinylpyridine 114 11 11 2-vinyl 5ethylpyridine 100 2-methyl-5-vinylpyridino 100 98 98 Phase separationoccurred with very little, if any, polymer being formed.

Example V Runs were made for the polymerization of four differentvinylpyridine compounds at 50 C. using two mols of acetic acid per molof the vinylpyridine. Polymerizations were efiected in accordance withthe following recipe:

Parts by weight Monomer 100 Water 300 K S O 0.9 Acid Variable Results ofpolymerization after 1.5 hours and 20 hours are shown below:

Acetic Conversion, percent Monomer acid,

parts 1.5 20 hours 2-vi.uylpyridine 114 6 10 4-vinylpyridine 114 5 182-vinyl-5-ethylpyridine 100 24 2-methyl-5-viuylpyridine 100 70 94 f 1Phase separation occurred with very little, if any, polymer being ormeExample VI Two runs were made. forfthe ,copolymerization of2-methyl-5-vinylpyridine at 5 0 C. in accordance with the followingrecipes:

1 One mol per mol 2-methyl-5-vmylpyridine. 2 Two mols per mol2-methyl-5-vinylpyr1dme.

Fluid latices were obtained in both runs. The latex from run H wasemployed asthe emulsifying agent for the polymerization of acrylonitrilein accordance with the following recipe:

Parts by weight Acrylonitrile 100 Water 600 Latex from run II (above) 15z z s 0. 9 NaHSO 0.5

Temperature, C 50 Time, hours I Conversion, per 98 A smooth, stablelatex wasobtained.-

Example VII A run was made for the polymerization of 3-vinylpyridine at50 -C.-in accordance with the following recipe:

Parts by weight B-Vinylpy'ridine 100 Water 300 K s o 0.9 NaHSO 0.5Acetic acid 25 A conversion of 76percent wasreached in 1.5 hours. Aftera total of 20 hours, no additional polymer was formed. At the end ofthis period 0.9 part by weight of K S O and 0.5 part by weight NaHSOwere introduced.

After another 1.5 hours, the polymerization had reached percentconversion.

Example VIII A run was made for the production of a styrene/Lmethyl-S-vinylpyridine copolymer at 50 C. using the following recipe:

' Parts by weight Styrene 50 Z-methyl-S-vinylpyridine 50 Water 300 K S O0.9 NaHSO 0.5 Acetic acid 50 After 1.5 hours the conversion had reached57 percent. Polymerization continued and reached a value of 93 percentafter 22 hours, the product being a stable fluid latex.

Example IX Runs were made for the production of methylmethacrylate/2-methyl-5-vinylpyridine copolymers at 50 C. In thefollowing tables are recorded the recipes and conversion for thesepolymers.

Parts byweight' Methyl methacrylate %methyl-5-vinylpyridine Conversion,percent, 1.5 hours Conversion, percent' 18 hours Conversion, percent, 22hours Example X Z-methyl 5 vinylpyridine was polymerized in the presenceof a considerable variety of acidic materials. In this example,polymerizations were effected in aqueous medium at 50 C. using therecipe of Example I and two equivalents of acid per mol of2-methyl-5-vinylpyridine.

The different acidic materials-used,- their amounts, and 2. Theprocessof claim 1 inwhich said 3-vinylpyridine the conversionreachedin;1.5'hoursaregiven-imthe comprises at least 10 percent byweight of -the total followingdableet r e monomeric mixture undergoingpolymerization.

3.- The process of claim 1 in which said acidic mate- 5 rial is aceticacid.

- Acidicmaterial S ub ty- 01 4. The process of claim 1 in which saidacidic material A 111100 cc. vers1on, V H were" lgnizatio water at per-18 succlmc acld; a Parts/19 F -a 20 cent- 5. The process .of cla1m.1 inwhichsaid acidic mate ype parts Lfihrsp I mono. a rial 1s prop1on1cacid.

I a 10* 6. The process of claim .1 inwhich said, acidic-mate. I h rialis sodium dihydrogen phosphate. Propionlc acid 122 1.32X10- m 98 Ynewbmmopmpiom 256 grgxmhh Soluble 7. The. processof cla1m..1 .m.wh1chsaid ac1d1c mate a 2 01: 18 81' 111' C 80 8. e Beam Y 210 h 6.3 Q3 1 52v 8. A latex produced by the process of claim 1.

' 100 6.6 10 7 109 9. A latex produced by the process of claim 3.

5% .kgfigf, 11(7) 83 104A latex produced by the process of claim 4. 24s3.7- 10 0.1 1o 11. Ailatex produced by the process of claim 5. Caprync I242 117x10 12 3 12. A latex produced by the process of claim. 6.

1 1 e 7 13. The process, which comprises polymerizing in 600 Parts Waterused the Paymematmn reclpeaqueous, solution. a salt ,of 2-methyl-5-vinylpyridine and an acidic material, said acidic material.havingan ioniza- The reaction mixtures were all clear, colorless solu-.i constant greater than -m and less than tions. it will be evident t athe acids ni e- 1.36 10 and a water solubility of at least 0.2 gramabove table all had an ionization constant 'of '1.36 ,10.- per 100 fwatepat 20 C,

1e55- w 7 5' 14. vThe process which comprises polymerizing in In theexamples It W111 he noted that a r' mo t. aqueous solution a salt of2-methyl-5-vinylpyridine and generally approximately 10 percent, ofpolymeric matei acid,

rial is produced with materials which are. OlltSid8 ,Of A process forpolymerizing a yridine compound the scopeof this invention; that is,2,-vinyland 4.-.vinylf h Structure pyridines, and polymerizationsconducted in thepresence' of less soluble acidic materials. Utilizingtheacidic I materials of the present invention and Z-methyl-S-Vinyl R R1pyridine, there is a conversion of at,least,,20 percent.in

1.5 hours at 50 C., in a persulfate or bisulfite-persulfate R system asthe sole catalyst. Of course, the amount of N conversion Will with themonomers p y and where R isselected from the groups consisting of thepolymerization conditions, but they are all on the CH same order. Whenhomopolymers of 3 -vinylpyridines a are prepared the conversion ispractically complete in :1.5 hours. As greater amounts of other monomersare added 40* are selected f the group consisting f hydro a becomes sHowever, the important P gen halogen; alkoxy and -alkyl-groups,-and R isselected ture is that the conversion will continue to, substantial f thegroup consisting f RI and R2 thetotalhumber a q V h V Y ofjcarbon atomsin said-R and-R being-not greater h f tunes also depehdeht P h absencethan '12; comprising formingan aqueous solution of -said mhlbltprs' h omWiymenzatlon mhlblfors P i compound and an acidic material, having anionization there may be an induction period before polymerizationconstant greater than 1.0 -m and mh 13 104 starts. Following thisinduction period, substantially and a water solubility of at least 02gram per 100 of Complete convelhiomcan Obtained, water. at 20 C., andpolymerizing the resulting salt. AS many POSSlblB lI1h9d1meI1t$ may bemade'oi-thl's 16. The process of claim 15 in which .said pyridinelnvention without departmg from the scope. thereof, 1t compoundcomprises at least 10 percent of th t t l is to he understood that allmatter herein set forthns monomer mixture undergoing l i ti to beinterpreted as lllustrative. and not as unduly limit- 7 The process f li 1 i hi h id idi t mg themven rial is benzoic acid.

I Cl 18. The process of claim 1 in which said acidic mate- 1. Theprocess. which comprisespolymerizing. in rial is phenoh aqueous solutiona saltof a monomeric 3J-V1nylpyr1d1ne; with an acidic material, saidacidic, material havinglan R f e Cit d in the file of thi atentionization constant at least 1.0 10. and less than 1.36 l0- and a watersolubility of at least 0.2 gram 7 UNITED STATESPATENTS per 100 cc. ofwater at 20 c, Harmon 1948 UNITED STATES PATENT OFFICE Certificate ofCorrection Patent No. 2,862,902 December 2, 1958 James E. Pritchard Itis hereby certified that error appears in the printed specification ofthe above numbered patent requiring correction and that the said LettersPatent should read as corrected below.

Column 3, lines 4 to 9, the formula should appear as shown below insteadof as in the patent:

R N/ R: column 6, line 63, in the table, first column thereof, for K S Oread K S O Signed and sealed this 14th day of April 1959.

Attest: KARL H. AXLINE, ROBERT C. WATSON,

Attestz'ng Oyficer. Commissioner of Patents.

1. THE PROCESS WHICH COMPRISES POLYMERIZING IN AQUEOUS SOLUTION A SALTOF A MONOMERIC 3-VINYLPYRIDINE WITH AN ACIDIC MATERIAL, SAID ACIDICMATERIAL HAVING AN IONIZATION CONSTANT AT LEAST 1.0X10-10 AND LESS THAN1.36X10-4 AND A WATER SOLUBILITY OF AT LEAST 0.2 GRAM PER 100CC. OFWATER AT 20*C.
 15. A PROCESS FOR POLYMERIZING A PYRIDINE COMPOUND OF THESTRUCTURE